Vertical Black line. I have a hyundai 42" plasma television model number: Hpt-4240. Recently i

Question

I have a hyundai 42" plasma television model number: Hpt-4240. Recently i have had a 1" black vertical line appear. Although It comes and goes it is there more often than its not. Its driving me nuts!!
I have checked thats its not coming in through the scart which is where Sky, Dvd and ps2 come in.
Any help/solution you can give would be greatly appreciated.
Cheers
Stezza